Seamed press felt including an elastic carrier layer and method of making

Abstract

A seamed press felt formed from a base fabric material including MD yarns arranged in two superimposed layers joined by the MD yarns at CD folds at opposing ends thereof to form a continuous unbroken tube-like structure. The MD yarns form loops at the folds to define a pintle channel. A generally planar yarn assembly including an array of polymeric yarns bonded to an elastic carrier material that is extensible by at least 1% is located inside the base fabric with the yarns of the array oriented in the CD. A high surface contact area material is bonded to the elastic carrier material at both exterior MD ends adjacent to the MD loops at the folds. Each of the MD ends is anchored in a fixed position adjacent to the loops at the folds. A pintle extends through the channel defined by intermeshing the loops from the opposing ends.

The invention claimed is: 
     
       1. A seamed press felt comprising
 a base fabric material having an MD length and CD width including at least MD oriented yarns and arranged in two superimposed layers joined by the MD oriented yarns at CD oriented fold regions at each of two opposing ends thereof, the MD oriented yarns forming uniform loops at the fold regions to define a channel extending the CD width of the press felt, 
 a generally planar yarn assembly including an array of mutually parallel and regularly spaced polymeric yarns, each bonded to an elastic carrier material that is extensible by at least 1% of a relaxed length thereof, the generally planar yarn assembly being located interior to the two superimposed layers of base fabric and is oriented such that the yarns of the array are oriented in the CD of the press felt, a high surface contact area material is bonded to the elastic carrier material at at least both exterior MD edges thereof that form the MD ends of the yarn assembly that are located adjacent to the loops formed of the MD oriented yarns at the fold regions and extend in the CD width direction, each of the MD ends is oriented parallel to the loops of the MD oriented yarns and is anchored in a fixed position adjacent to the loops at each of the fold regions, and 
 a pintle extending through the channel defined by intermeshing the loops from the two opposing ends to form a seam. 
 
     
     
       2. The press felt according to  claim 1 , wherein in the fixed position, the MD ends of the generally planar yarn assembly contact an MD outer surface of the loops from the opposing end of the base fabric. 
     
     
       3. The press felt according to  claim 1 , wherein in the fixed position, the MD ends remain within 1 mm of the MD outer surfaces of the loops from the opposing end of the base fabric. 
     
     
       4. The press felt according to  claim 1 , wherein the generally planar yarn assembly is anchored to the base fabric material adjacent to the loops and the high surface contact area material extends at least partially into the loops. 
     
     
       5. The press felt according to  claim 1 , wherein the base fabric is woven, and the MD ends extend past a last CD yarn of each of the superimposed layers adjacent to the loops. 
     
     
       6. The press felt according to  claim 1 , wherein the generally planar yarn assembly is anchored to the base fabric material at least in an area adjacent to the MD ends so that the exterior MD edge with the attached high surface contact area material extends a predetermined uniform distance into-the loops. 
     
     
       7. The press felt according to  claim 1 , wherein the high surface contact area material does not move from the fixed position by a distance greater than a width of the pintle that extends through the loops of MD oriented yarns. 
     
     
       8. The press felt according to  claim 1 , wherein the base fabric is woven. 
     
     
       9. The press felt according to  claim 1 , wherein the base fabric is non-woven. 
     
     
       10. The press felt according to  claim 1 , wherein the base fabric is one of an endless woven, modified endless woven, flat woven, multiaxial construction, or a non-woven construction. 
     
     
       11. The press felt according to  claim 1 , wherein the elastic carrier layer is one of: an elastomeric membrane, a permeable film, an elastic nonwoven mesh, a woven assembly of elastomeric yarns, a knitted material, or a nonwoven loosely bonded fibrous scrim. 
     
     
       12. The press felt according to  claim 1 , wherein the elastic carrier layer is a nonwoven loosely bonded fibrous scrim. 
     
     
       13. The fabric according to  claim 12 , wherein the nonwoven loosely bonded fibrous scrim material is a thermally bonded nonwoven open network of continuous polyamide fibers having a dtex in the range of 1 to 10, and an air permeability of from about 100 cfm (˜1560 m 3 /m 2 /hr) to about 2,000 cfm (˜31,000 m 3 /m 2 /hr) or more. 
     
     
       14. The press felt according to  claim 1 , wherein the high surface contact area material is selected from: a strip of nonwoven fibrous material, at least one multifilament or cabled monofilament. 
     
     
       15. The press felt according to  14 , wherein the high surface contact area material in the seam region of the press felt is maintained within 1 mm of the fixed position. 
     
     
       16. The press felt according to  claim 1 , wherein the polymeric yarns of the yarn assembly are at least one of single, multicomponent or cabled, and are comprised of a polymer selected from a polyamide and a polyurethane. 
     
     
       17. The press felt of  claim 1 , wherein an additional one of the generally planar yarn assemblies is located on at least one of an upper external surface of the generally planar flattened tube-like textile structure or a lower external surface of the generally planar flattened tube-like textile structure. 
     
     
       18. The press felt according to  claim 1 , wherein the generally planar yarn assembly comprises:
 a first outside yarn panel, at least one interior yarn panel, and a second outside yarn panel, 
 the first and second outside yarn panels each including multicomponent yarns or other high surface contact area material yarns at an exterior MD edge that extend in a position located adjacent to the CD oriented folds, the multicomponent yarns or other high surface contact area material yarns having a spacing that is the same as the array of mutually parallel and regularly spaced apart polymeric yarns of the interior yarn panel, and 
 the first and second outside yarn panels have a bonded connection to edges of the interior yarn panel. 
 
     
     
       19. The press felt according to  claim 18 , wherein the bonded connection is an ultrasonic weld. 
     
     
       20. The press felt assembly according to  claim 18 , wherein
 one of the multicomponent yarns or other high surface contact area material yarns in the first outside panel is located in an interior of the first fold region of the base fabric, parallel to, and in contact with interior surfaces of the MD yarn loops at the CD oriented first fold region. 
 
     
     
       21. The press felt assembly according to  claim 20 , wherein
 one of the multicomponent yarns or other high surface contact area material yarns in the second outside panel is located in an interior of the second fold region of the base fabric, parallel to, and in contact with interior surfaces of the MD yarn loops at the CD oriented second fold region. 
 
     
     
       22. The press felt according to  claim 1 , wherein a void volume of the press felt is adjustable by adjusting a spacing between yarns in the array of yarns of the generally planar yarn assembly. 
     
     
       23. The press felt according to  claim 22 , wherein the spacing is adjusted based on an amount of stretching of the elastic carrier material. 
     
     
       24. The press felt according to  claim 1 , wherein the elastic carrier material is stretched at least 2%. 
     
     
       25. The press felt according to  claim 1 , wherein the base fabric material comprises a plurality of spirally wound turns of a first fabric structure, the first fabric structure including:
 a first planar yarn array of the MD oriented yarns comprising single polymeric monofilaments arranged at a first density, 
 at least two layers of a hot melt adhesive web having a first melting temperature, one of the layers of the hot melt adhesive located on each side of the first planar yarn array, and 
 a layer of a fine fibrous scrim material-located over each of the layers of the hot melt adhesive web, 
 wherein the first yarn array, the two layers of the hot melt adhesive web, and the layers of the fine fibrous scrim material located over the two layers of the hot melt adhesive web are heated above the first temperature to form the first fabric structure, and 
 
       each adjacent one of the wound turns of the first fabric structure is oriented at an angle to the MD and is bonded to an adjacent turn to provide a flattened continuous double layer tube. 
     
     
       26. The fabric according to  claim 25 , wherein the fine fibrous scrim material is a thermally bonded nonwoven open network of continuous polyamide fibers having a dtex in the range of 1 to 10, and an air permeability of from about 100 cfm (˜1560 m 3 /m 2 /hr) to about 2,000 cfm (˜31,000 m 3 /m 2 /hr) or more and which has a second melting temperature that is higher than that of the first melting temperature. 
     
     
       27. The fabric according to  claim 25 , wherein the yarns of the first array are circular in cross-section and have a first diameter. 
     
     
       28. The fabric according to  claim 25 , wherein the yarns of the first array are single circular cross-sectional shaped monofilaments having a diameter of 0.2 mm to 0.6 mm arranged at a yarn density of from 15 to 40 yarns/inch (5.9 to 15.7 yarns/cm). 
     
     
       29. The fabric according to  claim 25 , wherein the CD yarns of the generally planar yarn assembly are single circular cross-sectional shaped monofilaments having a diameter of 0.2 mm to 0.6 mm arranged at a yarn density of from 15 to 40 yarns/inch (5.9 to 15.7 yarns/cm). 
     
     
       30. The fabric according to  claim 25 , wherein the CD yarns of the generally planar yarn assembly are cabled monofilaments having a diameter, d, in the range of 0.1 to 0.3 mm. 
     
     
       31. The fabric according to  claim 30 , wherein the cabled monofilaments are cabled in one of a d×2×2, d×2×3 or d×3×3 arrangement. 
     
     
       32. The fabric according to  claim 25 , wherein the MD oriented yarns of the first array are circular in cross-section and have a first diameter, the CD yarns of the generally planar yarn assembly are circular in cross-section and have a second diameter, and the first diameter is greater than or equal to the first diameter. 
     
     
       33. The fabric according to  claim 25 , wherein the fibers of the fine fibrous scrim material have a dtex (mass in grams per 10,000 meters of fiber) which is in the range of from about 1 to 10. 
     
     
       34. The fabric according to  claim 33 , wherein the fibers of the fine fibrous scrim are comprised of polyamide-6/6 (PA-6/6) which are periodically bonded together to form a highly open loosely cohesive scrim material having an air permeability of at least 100 cfm (˜1560 m 3 /m 2 /hr). 
     
     
       35. The fabric according to  claim 34 , wherein the scrim material has a tensile strength of at least 5 lb/in. 
     
     
       36. The press felt according to  claim 1 , wherein base fabric material comprises a plurality of spirally wound turns of a first fabric structure, the first fabric structure including:
 a first array of the MD oriented yarns comprising single polymeric monofilaments and a second array of CD oriented yarns interwoven with the MD oriented yarns in a plain weave, and 
 
       each adjacent one of the wound turns of the first fabric structure is oriented at an angle to the MD and is bonded to an adjacent turn to provide a flattened continuous double layer tube. 
     
     
       37. A method of making a press felt, comprising:
 providing a base fabric including at least lengthwise extending MD yarns arranged in two superimposed layers joined by the MD oriented yarns at CD oriented fold regions, the base fabric having a desired MD length and CD width, the MD oriented yarns forming first loops at a first one of the fold regions and forming second loops at a second one of the fold regions, and the first and second loops are adapted to be interdigitated to define a uniform channel extending the CD width of the press felt; 
 forming a planar yarn assembly comprising an array of mutually parallel component yarns, by arranging the component yarns mutually parallel and at a desired spacing, and laminating the component yarns to an adhesive web under heat and pressure in a continuous process, and bonding the laminated component yarns to a nonwoven, elastic carrier material, the elastic carrier being stretchable allowing the planar yarn assembly to be stretchable in a direction essentially perpendicular to an orientation of the yarns of the array, the planar yarn assembly extends from one of the fold regions to the opposite fold region of the base fabric in a single layer, and at least some of the component yarns at first and second exterior edges of the planar yarn assembly are formed of a high surface contact area material; 
 locating the planar yarn assembly interior to the two superimposed layers of base fabric with the first end of the planar yarn assembly extending at least partially into the MD yarn loops at the fold region; 
 fixing the first end of the planar yarn assembly in position so that a first component yarn is in the desired position adjacent or extending partially into the MD yarn loops of the base fabric, and then stitching, sewing or otherwise bonding the first end to the base fabric; 
 extending the planar yarn assembly towards the opposite fold region of the base fabric, the MD length of the yarn assembly being at least 1% less than an overall interior flattened length of the base fabric, and uniformly tensioning the planar yarn assembly across its CD width so as to stretch the elastic carrier with the laminated yarns attached to it by an amount sufficient to bring the second end into position adjacent to the seam loops; 
 clamping the second end of the planar yarn assembly in position so that a last component yarn is in the desired position adjacent or extending partially into the MD yarn loops of the base fabric, and then stitching, sewing or otherwise bonding the second end to the base fabric. 
 
     
     
       38. The method of  claim 37 , wherein forming the planar yarn assembly further comprises:
 forming a plurality of laminated yarn panels, each including the component yarns that are mutually parallel and at a desired spacing, and assembling a plurality of the yarn panel to form the planar yarn assembly. 
 
     
     
       39. The method of  claim 38 , wherein forming the planar yarn assembly further comprises:
 arranging lateral edges of each of the yarn panels such that a lap join can be formed in which the component yarn spacing is maintained. 
 
     
     
       40. The method of  claim 39 , wherein forming the planar yarn assembly further comprises:
 cutting each of the yarn panels to a length equal to the CD width of the base fabric; and connecting together a sufficient number of yarn panels so that, when joined and bonded edge to edge, the planar yarn assembly is at least 1% shorter than the interior flattened MD length. 
 
     
     
       41. The method of  claim 40 , wherein forming the planar yarn assembly further comprises:
 providing exterior edges of the first and last yarn panels of the planar yarn assembly which will be located adjacent the fold regions of the base fabric with the high surface contact area material. 
 
     
     
       42. The method of  claim 41 , wherein the high surface contact area material comprises at least one of a strip of nonwoven fibrous material, a multifilament or a cabled monofilament.